How did they do on fuelefficiency with the Ram 50? Well, pretty darn good it seems. In this ad, the four-wheel-drive turbodiesel had an EPA rating of 40 mpg highway. With 40 mpg and an 18-gallon fuel tank the Ram 50 would’ve had a cruising range of 720 miles. That’s pretty impressive.

This Ram 50 ad got us thinking about how cool it would be, now that fuel prices are climbing to absurd levels here in 2012, if the manufacturers offered a compact pickup powered by an economical turbodiesel engine. It would be dandy if buyers had the option of a body-on-frame, diesel-powered, small pickup truck that gets 40 mpg. Heck, even 35 mpg would be welcome. We hope that a pickup truck like this is in our future. After all, there’s already one in our past.

Do you drool over diesels? Well, if you’d like to convert your gas-powered rig to diesel power, there are actually a surprising number of companies that specialize in these conversions. Some offer problem-solving parts and kits, others offer complete in-house conversions, and a few offer the whole enchilada with parts, kits, and the option of a complete in-house conversion.

Following is a list of companies that can help you complete a diesel conversion. We’ve tried to include companies that cover a wide range of makes and models of trucks. Some of the engine swaps are mainstream, while others use the less prevalent Toyota, Mercedes-Benz, and Volkswagen diesel engines.

So if you’re in the market to go diesel, start here.

Bruiser Conversions Getting a Cummins 4BT in your Jeep CJ, YJ, TJ, or JK is as easy as dropping your rig off at Bruiser Conversions. You can choose from two automatic transmissions and one manual transmission. If you wish to complete the conversion, the company offers components to install a 4BT into your CJ, YJ, or TJ. There are a slew of upgrades available as well.Contact: 727/709-0239, www.bruiserconversions.com

Mash Motors How about Duramax LBZ power under the hood of your Hummer H1, H2, or large GM SUV? Well, Mash Motors can make it happen. The in-house conversion includes an Allison M1000 heavy-duty six-speed automatic transmission, two-speed part-time transfer case, Duramax wiring harness, modified ECM, custom 4-inch-diameter exhaust, and much more. Performance upgrades include a head stud kit, 60 psi turbo, power programmers, water injection, propane injection, high-flow fuel injectors, and more. Mash Motors says build time is approximately 45 days for a H1 and 25 days for the H2. Contact: 316/617-2472, www.mashmotorsinc.com

HPA Motorsports Got a Jeep YJ or TJ? If you’d like the benefits of a Volkswagen TDI engine you can either purchase one of HPA Motorsports do-it-yourself kits or you can let the company complete the conversion in-house. The DIY kits are available in two stages. Stage 1 is a bare bones grouping that is intended for those who wish to take on the fabrication and plumbing of the TDI’s boost track, gas pedal fitment, and so on, and have the resources available to tune the engine software around their final configuration. Stage 2 builds on the Stage 1 package, adding the engineered air-to-water intercooling system, a performance ECU tune that has reconfigured the injection around the ultra-efficient boost track, a bracket for the gas pedal fitment, and key coolant line fittings to better facilitate the Volkswagen cooling system. HPA mates the VW turbodiesel engine to specific manual transmissions and the company is developing a kit to install the engine in the Jeep JK. Contact: 604/598-8520, www.hpamotorsports.com

Destroked If you want to replace the Power Stroke turbodiesel in your Ford truck with a Cummins turbodiesel, Destroked has a wide range of components to make it happen. The company has motor mounts, engine controllers, fan shrouds, alternators, throttle accessories, flex plates, and starters, among other things. Destroked also offers a wide variety of adapter plates to mate the Cummins’ engines to a variety of transmissions including Ford and ZF and even GM and Allison. The company also offers a stand-alone controller for the Allisontransmission as well as Ford and GM transmissions. Contact: 720/897-7477, www.destroked.com

Predator Inc. Those of you with a Hummer H1 or H2 can have Predator Inc. fit your rig with a Duramax/Allison combination. The conversion includes a part-time two-speed transfer case, intercooler, fuel cooler, Duramax wiring harness, modified ECM, and “several hundred other items that go into the massive conversion process.” If you have an H1 you also have the option of a Cummins 6BT with either an Allison or 4L80E transmission. With each conversion there are a significant number of performance upgrades available.Contact: 877/733-2867, www.predatorinc.com

Jeff Daniel’s Jeep Customizing If you want to put a Cummins 4BT diesel engine into your Jeep CJ, YJ, TJ, or JK, Jeff Daniel’s Jeep Customizing has the components needed to complete the swap. The company says it’ll take you about 60 hours to complete the conversion. Components can be purchased from the company either as a kit or al a carte. The engine and transmission is not included, but the company says it can help locate them. Jeff Daniel’s Jeep Customizing offers cool components like engine mounts that are designed to absorb the vibration of the engine as well as provide a simple install. The company also offers a slew of parts and accessories including adapters, bellhousings, and flywheels. Contact: 215/256-8090, www.jdjeeps.com

Proffitts Cruisers Got a LandCruiser? Proffitts Cruisers can perform an in-house conversion to the 3.3L Cummins, 3.9L Cummins, or a Toyota turbodiesel engine. The company says it has installed over 70 4BT conversions into a variety of Land Cruisers. When it comes to Toyota turbodiesel engines Proffitts says the most common engines used in its conversions are the six-cylinder variants offered from 1986-up, which are the 12HT, 1HZ, 1HDT, 1HD-FT, and the computer-controlled 1HD-FTE. Pictured here is a ’94 FZJ80 Land Cruiser fitted with the 1HD-FT Toyota six-cylinder diesel engine mated to a five-speed manual transmission. The company says this is the most complicated conversion it performs because the donor vehicle is right-hand-drive and it takes over 50 hours to mate the wiring harness to the left-hand-drive harness. Contact: 877/PROFFITT, www.proffittscruisers.com

Diesel Conversion Specialists If you want to repower your Ford truck with a Cummins turbodiesel engine you can either send the truck to Diesel Conversion Specialists and have them fit it for you or you can purchase the conversion parts and do it yourself. The company offers engine mounting kits to fit a 12- or 24-valve Cummins turbodiesel engine in ’69-’79 Ford trucks and 12- or 24-valve or ’03-up Cummins common-rail engine in ’80-’97 and ’99-up Ford trucks. Diesel Conversion Specialists also offers rebuilt and used Cummins engines as well as a wide range of parts and accessories including a number of transmission adapter plates.Contact: 406/755-8878, www.dieselconversion.com

Need a Cummins? One of the vendors at this year’s Red Rock 4-Wheelers Easter Jeep Safari in Moab, Utah, was ACD Engines (877/506-8667, www.acdengines.com). ACD is like a Cummins superstore. The company is a great source for new Cummins turbodiesel engines and offerings include the 4BTAA, 6BTA, and 6CTA. If you don’t need a complete engine ACD also offers long-blocks including the 4BT, 6BT, and 6CT. Also available are a wide variety of parts, rebuild kits, used engines, used transmissions, and even installation of Cummins engines into the Jeep JK.

H-Line Conversions Since its start in the early ’90s this company has fitted diesels into a wide variety of vehicles, including a ’65 Chevy Impala. So far, H-Line has converted over 100 Hummer H1s and 60 Hummer H2s to Duramax turbodiesel power. H-Line can provide you with a do-it-yourself kit or the company can do the swap for you. In addition to the H1 and H2, H-Line can convert many GM fullsize SUVs to Duramax power as well. Conversion packages include the basic 500 horsepower economy package and the high-performance 850 horsepower package. Contact:www.hlineconversion.com

Eco-Offroad Eco-Offroad can do an in-house diesel conversion on your Toyota FJ-45 pickup, FJ-40 Land Cruiser, Land Rover Series II, IIA, or III, or Land Rover Defender. Depending on your vehicle and needs, the company fits the Cummins 3.3L or 3.9L 4BT, 2.8L IH, Mercedes OM617, or Isuzu turbodiesel engines. Contact: 541/550-6300, www.eco-offroad.com

4x4 Labs If you’d like to fit a Mercedes-Benz OM617 five-cylinder turbodiesel into your rig, 4x4 Labs can help. At the time of this writing the company offers transmission adapter kits for GM manual transmissions (including SM420, SM465, NV3500, NV4500, and NV5600) as well as Toyota W56 five-speed, R150-151 five-speed, and Land Cruiser four- and five-speed manual transmissions. In development is an adapter kit for the Aisin-Warner AX15 five-speed manual transmission. 4x4 Labs is also starting development on adapters to mate later six-cylinder turbocharged OM603/606 engines to the same lineup of transmissions.Contact: 530/477-0140, www.4x4labs.com

Domino Effect If you convert your rig to diesel and the power output is increased over your previous powerplant, you may have to beef your rigs driveline. There are many variables to this of course, depending on which dieselengine you’ve installed and whether or not you’ve already made driveline upgrades.

We wondered how the OE manufacturers approached this increase in power, so we contacted Chrysler and asked about the driveline differences between a gas-powered ’12 Ram 2500 and a diesel-powered Ram 2500. The Cummins turbodiesel makes 800 lb-ft of torque, which is double the torque of the Hemi V-8. The diesel-powered Ram gets a beefier 68RFE six-speed automatic transmission, but uses the same transfer cases (manual- or electric-shift) as the gas-powered trucks. The driveshaft U-joints in the diesel-powered Ram 2500 are larger 1485 series ’joints as opposed to the 1415 series ’joints found in the gas-powered trucks. Finally, the diesel-powered rig is equipped with an 11.5-inch rearend, which has a higher torque capacity than the 10.5-inch rearend in the gas-powered truck